1. Field of the Invention
The present invention relates to an electronic packaging arrangement. More particularly, the present invention relates to an electronic packaging arrangement employing a heat spreader designed to facilitate multiple and reworkable heat sink attachment directly to chip carrier.
2. Background and Related Art
As the integrated circuit art moves toward smaller and smaller component sizes leading to increased density of circuits and more and more input/output (I/O) connections, the heat generated by such increased density increases correspondingly. Moreover, with such increased density, the cost of integrated circuit packages, such as flip chip packages, also increases.
Thus, efficient cooling and reworkability of such packages is highly desirable. Accordingly, where electronic device failure of the package occurs, efficient heat dissipating structure should be such as to be readily removed in non-destructive manner.
Typically, heat sink arrangements employing heat fins are positioned in thermal contact with the integrated circuit package mounted on a printed circuit board (PCB). The heat sink is, in turn, removably attached to the printed circuit board. An elastomeric thermal pad or thermal grease may be interposed between heat sink and integrated circuit package to compensate for any mismatch in physical characteristics and thermal expansion between heat sink and integrated circuit package, as well as reduce interface resistance. An example of such an arrangement may be found in U.S. Pat. No. 6,125,037. One of the difficulties in cooling integrated circuit packages is thermally contacting a sufficiently large heat dissipating surface to the integrated circuit to effectively spread heat generated therefrom. Packaging constraints often limit the area size of the heat dissipating surface, particularly where such packages are designed to be reworkable. Moreover, integrated circuit products, such as, single chip flip chip modules, often employ different cooling arrangements for the same product. For example, flip chips may be employed in a single chip module using some form of clip to hold the heat sink in thermal contact with the chip on the PCB. Alternatively, the heat sink may be attached by screws or posts to the PCB.
In accordance with the present invention, a packaging arrangement is provided wherein a heat sink and heat spreading lid are directly attached to the chip carrier. The heat spreading lid is sufficiently large to accommodate effective spreading of heat from the chip and yet is designed to allow heat sink attachment by either posts positioned directly on the chip carrier at its corners, or by some form of chip arrangement clamped to the underside of the lid or chip carrier at the mid-section of the heat sink.
It is, therefore, an object of the present invention to provide an improved integrated circuit package.
It is a further object of the present invention to provide an integrated circuit package with improved cooling.
It is yet a further object of the present invention to provide an improved reworkable flip chip package.
It is yet still a further object of the present invention to provide an improved heat sink attachment arrangement wherein the heat sink is attached directly to the chip carrier.
It is another object of the present invention to provide a removable heat sink and heat spreading lid that provides effective chip cooling, with said heat spreading lid arranged to facilitate heat sink attachment to the chip carrier by posts arranged on the carrier or by clipping to the lid or carrier.
It is yet another object of the present invention to provide a chip module having attachment posts on the chip carrier for attaching a heat sink directly to the chip carrier, and a heat spreading lid interposing the heat sink and chip or chips with the surface area of the lid being approximately the size of the surface area of the chip carrier so as to effectively spread heat, protect the chip(s) and facilitate heat sink attachment by either the attachment posts or a heat sink clip acting to clamp the heat sink to the chip carrier.
These foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings, wherein like reference members represent like parts of the invention.